Troubleshooting and Departure Preps for Station Crew

The Expedition 25 crew’s work with the Air Revitalization System rack in the International Space Station’s Tranquility node continued Thursday as Flight Engineers Scott Kelly and Shannon Walker checked clearances and collected measurements to determine what prevented the removal of the Carbon Dioxide Removal Apparatus (CDRA) on Wednesday.

Part of the environmental control and life support system, the CDRA removes carbon dioxide and trace contaminants from the station’s atmosphere.

Using a rigid plastic sheet, Kelly probed for obstructions around the rack while Walker used a video camera to provide a close-up look of the troubleshooting activities for the teams at Houston’s Mission Control Center. Kelly and Commander Doug Wheelock were unable to remove the unit and gain access to an absorbent bed Wednesday. They proceeded to remove a second one to prepare the CDRA for the arrival of a replacement adsorbent bed being delivered by space shuttle Discovery in December.

Wheelock began his workday Thursday with a session with the VO2max experiment, which studies changes in the astronauts’ aerobic capacity during long-duration spaceflight. NASA is interested in tracking these changes because a reduction in maximum oxygen uptake directly impacts a crew member’s ability to perform strenuous activities such as spacewalks or emergency operations. Data from this research may also provide valuable insight into the aerobic capacity of teams in closed environments on Earth, such as arctic bases and submarines.

Cosmonauts Alexander Kaleri and Oleg Skripochka, both flight engineers, wrapped up the reconfiguration of the Pirs docking compartment airlock following Monday’s spacewalk by Skripochka and Flight Engineer Fyodor Yurchikhin. The spacewalk to outfit the Russian segment of the station for future assembly work and experiments lasted six hours and 27 minutes.

As the end of Expedition 25 draws near, Wheelock, Walker and Yurchikhin kicked off a week of departure preparations, gearing up for their landing in the northern steppe of Kazakhstan aboard the Soyuz TMA-19 spacecraft on Nov. 25 at 11:46 p.m. EST (Nov. 26 at 10:46 a.m. Kazakhstan time). Their undocking will mark the beginning of Expedition 26 under the command of Kelly, who will remain aboard the station with Kaleri and Skripochka until March 2011.